This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This service project aims to provide a source of normal human blood to UCI investigators whose projects have been approved by the UCI GCRC Advisory Committee and the UCI IRB. Donors are assured of a controlled clinical setting for their blood to be drawn by certified phlebotomists or Registered Nurses, and investigators are assured that the donors, whose specimens they obtain throug the service, have been screened on entry into the Program and annually thereafter for hepatitis B and C and Human immuno-deficiency virus. Hemoglobin concentrations will be determined prior to every donation to protect the donor from phlebotomy-induced anemia. The donor pool also provides the investigators with a mix of gender and minority volunteers. Finally, the volunteers will be assured that the research projects involved have met critical peer review for both safety and scientific criteria.